1. DATA COMMUNICATION
Lecture-12

2. Recap of Lecture 11 Signals Analog and Digital
Analog and Digital Data & Signals
Periodic & Aperiodic Signals
Sine Waves and its Characteristics

3. Overview of Lecture 12 Sine Waves and its Characteristics
Control of Signals
Time and Frequency Domain
Composite Signals

4. Period and Frequency

5. Example 4.3 A Sine wave has a frequency of 6 Hz. What is its period?
Solution

6. Example 4.5
A Sine wave completes one cycle in 4 seconds. What is its frequency?
Solution:

7. Another Way to Look at Frequency
Measurement of the rate of change
How fast the wave moves from its lowest to its highest point
Changes in Short Time: High Frequency

8. Two Frequency Extremes
No change at all 
Zero frequency
Instantaneous changes 
Infinite frequency

9. Phase
Phase describes the position of the waveform relative to time zero
Phase describes the amount of backward or forward shift of the waveform
Measured in Degrees or Radians

10. Phase

11. Example 4.7
A sine wave is offset of a cycle with respect to time zero. What is its phase?
One Cycle = 360 Degrees
of a cycle = = 60 Degrees

12. Control of Signals Signal can be controlled by three attributes:
Amplitude
Frequency
Phase

13. Control of Signals- Amplitude

14. Control of Signals- Frequency

15. Control of Signals- Phase

16. Time and Frequency Domain

17. Time and Frequency Domain Example

18. Composite Signals

19. Summary Sine Waves and its Characteristics Control of Signals
Time and Frequency Domain
Composite Signals

20. Suggested Reading
Section 4.4, 4.5 “Data Communications and Networking” 2nd Edition by Behrouz A. Forouzan